A discharge device for a liquid material in a form of a so-called sealer gun, which is used for coating/filling work of coating or filling a liquid material, such as a coating agent or a filler, into or onto a gap or a space of a structure, is configured such that, as shown in FIG. 1, the base side of a discharge cylinder 1 formed in a barrel shape equipped on its tip side with a nozzle 10 configured to discharge a liquid material is connected to a main body a that is shaped into a hollow cylinder; the discharge cylinder 1 is communicated via an internal space of the main body a to an introduction pipe 30 that is connected to the internal space of the main body a; the body a accommodates therein a valve mechanism 2 configured to disconnect and to establish communication between the introduction pipe 30 and the nozzle 10 of the discharge cylinder 1; a holding unit 3 that is shaped in a continuously integrated manner with the body a is formed and provided on the outer circumferential side of the introduction pipe 30 connected to the main body a; a grip member 4 configured capable to be gripped together with the holding unit 3 is arranged on the forward side of the holding unit 3, and the upper side of the member 4 is axially supported by a spindle 40 on the upper side of the body a, so that it is configured to pivot to a position along the holding unit 3 by gripping it together with the holding unit 3, and to pivot to a position separate from the holding unit 3 with a resilient spring (not shown) by releasing a grip; and the grip member 4 is interlocked with the valve mechanism 2 such that the valve mechanism 2 accommodated inside the body a described above can open and close a communication aperture provided between the internal space of the body a and the discharge cylinder 1 through pivoting operation of pivoting by gripping the grip member 4 and resilient pivoting, accordingly, upon operation of gripping the grip member 4, a liquid material is discharged from a tip aperture 10a of the nozzle 10 by opening the valve mechanism 2, and upon releasing a grip on the grip member 4, a discharge of a liquid material is stopped.
According to the sealer gun A, when a discharge of a liquid material is stopped by releasing the grip member 4, a dripping phenomenon arises that the liquid material sticks and remains onto the tip portion of the nozzle 10 in a state of hanging like an icicle.
When a discharge of a liquid material is stopped, if the liquid material sticking and remaining as a drip on the tip of the nozzle 10 is left, as it is exposed to outside air, it can be denatured to a liquid material with properties unable to be normally used when performing coating work or filling work next time, therefore, it is treated by wiping out and discarding from the tip of the nozzle 10 immediately after when a discharge is stopped.
The sealer gun has a problem that workability of coating/filling work is inefficient due to the work of wiping out dripping each time when stopping discharge of a liquid material, and a problem that discard of dripping results in a loss of a liquid material.
It is thought that the dripping that a liquid material sticks and remains like hanging from the tip portion of the nozzle when a discharge of a liquid material is stopped cannot be shut off clearly because a liquid material of a coating agent or a filler has viscous properties and high adhesion and cohesiveness; and because a liquid material is pressurized and then sent and supplied into the discharge cylinder, the liquid material inside the discharge cylinder is pushed out with a remaining pressure on the liquid material in the discharge cylinder 1 when discharge is stopped by closing the valve mechanism 2.
As a countermeasure to this, a considerable means can be such that, as shown in FIGS. 2 and 3, a stop valve sv that operates, by operating the grip member 4, to open and to close together with the valve mechanism 2 accommodated in the body a is integrated in a region very close to the tip aperture 10a of the nozzle 10 of the tip of the discharge cylinder 1, so that the liquid material remaining in the discharge cylinder 1 under a pressurized condition when a discharge of a liquid material is stopped by releasing the grip member 4 and closing the valve mechanism 2 is made little in quantity only as much as that present in a very short distance between the tip aperture 10a of the discharge cylinder 1 and the stop valve sv; and a considerable means can be such that, as shown in FIGS. 4 and 5, a check valve cv that operates to close by pushing a valve body to a seat surface with a spring and to open with a pressure of a liquid material sent into the discharge cylinder 1 by gripping the grip member 4 is provided in a region very close to the tip aperture 10a on the tube tip of the nozzle 10 of the discharge cylinder 1, and sandwiching plates 11 configured to be closed as opposed in pair are mounted and provided via an elastic material 12 on an outer region of the tube tip of the nozzle 10, and when the liquid material is discharged from the tip aperture 10a of the nozzle 10, opposed portions of the sandwiching plates 11 having been closed together turn opened with a discharge pressure of the liquid material, and when a discharge of the liquid material is stopped, the sandwiching plates 11 are closed together and shut off the liquid material at the front of the tip aperture 10a of the nozzle 10.
However, among these means, in the former case, when a discharge of a liquid material is stopped, as depicted by a dot and dash line in FIG. 3, a phenomenon that the liquid material sticks and remains in a dripping state like an icicle hanging from the tip portion of the nozzle 10 still occurs.
It is thought that this is caused by pulling back like hoisting up the liquid material that has been already discharged out from the tip aperture 10a of the nozzle 10, with adhesion and cohesiveness originated by viscous properties of the liquid material.
Moreover, also in the latter case, when a discharge of a liquid material is stopped, a phenomenon that a liquid material sticks and remains in a dripping state like an icicle hanging from the tip portion of the nozzle 10 occurs. In the latter case, although a discharged liquid material is shut off by the sandwiching plates 11 at an outer side position of the tube tip of the nozzle 10, a liquid material that has been already discharged via an opposed space between the sandwiching plates, as depicted by a dot and dash line in FIG. 4, becomes sticking on the outer surface of the sandwiching plates 11 and hanging, resultantly, a dripping phenomenon occurs. Furthermore, because an area on the outer surface of the sandwiching plates 11 that is a sticking surface is wider than the circumferential surface of the tube tip of the nozzle 10, more dripping in quantity is produced than that in the former case. These means cannot achieve dripping prevention.